How Much Are Your Cartridge Filters Really Costing You?
Calculate the true OPEX of cartridge-based RO pre-filtration – and see what you’d save by switching to Filtersafe automatic screen filtration.
Cartridge filters have a cost that goes well beyond the price of the cartridges themselves. Every replacement cycle requires labor, generates solid waste that must be disposed of, and imposes a continuous energy penalty as pressure drop builds across fouled elements – right up until the moment they are changed.
Filtersafe’s Process Comparison Calculator lets you enter the real parameters of your operation and generates a side-by-side cost breakdown across three categories: energy, hardware and consumables, and labor. The result is an annualized OPEX figure for both technologies, based on your specific flowrate and site conditions.
Enter your total pre-filtration flowrate to get started. All other parameters have engineering defaults that can be adjusted to reflect your actual costs and conditions.
Hardware Parameters
This section accounts for the physical cost of the cartridge replacement cycle itself:
- Annual Replacement Rate — how many times per year cartridges are replaced (default: 6 times/year)
- Average Energy Loss — the computed average head loss across a full cartridge lifecycle, derived from the new and used cartridge values above (default: 0.5 bar)
- Energy Loss on a newly installed cartridge — head loss at the start of a cycle (default: 0.2 bar)
- Energy loss on a used cartridge — head loss just before replacement is required (default: 1.2 bar)
- Nominal flowrate per cartridge candle — the rated flow capacity of a single cartridge element (default: 3.8 m³/h), used to calculate the total number of cartridges required for your system
- Cost per cartridge element — the unit price of a single cartridge candle (default: $5)
- Annual Disposal Costs — the cost of solid waste disposal for spent cartridges each year (default: $1,500)
These inputs together determine the true annual consumables cost: not just purchasing cartridges, but replacing and disposing of them on a recurring basis.
Energy Parameters
The energy cost of cartridge pre-filtration is driven by pressure drop — the resistance the pump must overcome to push water through the filter elements. A new cartridge creates a head loss of around 0.2 bar; by the time it needs replacing, that typically rises to 1.2 bar or more. Because this cycle repeats continuously, the average head loss — and therefore the average energy consumed — is significantly higher than what a clean cartridge alone would suggest.
This section captures:
- Energy Cost per kWh — your local electricity tariff (default: $0.10/kWh)
- Pump Efficiency — the mechanical efficiency of your pump system (default: 0.78)
- CO₂ Footprint per kWh — the carbon intensity of your electricity supply (default: 0.707 kgCO₂/kWh), used to calculate the emissions impact alongside the financial cost
Filtersafe automatic screen filters maintain a consistently low and stable pressure drop, eliminating the energy penalty of fouling entirely.
Labor Parameters
Cartridge replacement is a labor-intensive process. At scale – for example, in a large desalination plant with thousands of cartridge candles per housing – the manpower required to execute each replacement cycle is substantial.
- Annual Work Days: Total working days per year dedicated to cartridge replacement tasks (default: 147 days/year)
- Cost per Work Day: The fully-loaded daily cost of skilled labor for this work (default: $670/day)
Filtersafe automatic screen filters backwash continuously and autonomously. There are no cartridges to pull, inspect, or replace, and no associated labor cost.
Results Interpretation
The calculator produces an annualized cost comparison across all three categories — energy, consumables, and labor — for cartridge filtration versus Filtersafe automatic screen filtration at your specified flowrate.
The outputs are designed to be used directly in OPEX modelling, budget justifications, and technology selection documentation. If you’d like a formal cost analysis for a specific project, contact us.